Sedentary habits in middle-aged individuals are associated with increased risk for cardiovascular disease. Studies examining this association typically have assessed physical activity participation in a narrow window, (for example, 1 week or 1 month) relative to probable disease etiology and progression. The possible relation of long-term physical activity patterns over decades or a lifetime to disease risk is not known because there currently exists no validated method of determining such exposure, but such studies are needed. The goal of this project is to validate self-report methods to assess long-term recall of participation in physical activity. The specific aims of the proposed research are to compare long-term recall of physical activity up to 15 years in the past with physical activity reports and physical fitness levels assessed at the baseline examination. Data to be analyzed for this project are from a cohort that has been under observation in the Aerobics Center Longitudinal Study. Baseline preventive medical examinations were given to 6,902 men and women during the interval from 1971-1982. Current physical activity and physical fitness levels maximal exercise treadmill test) were assessed at baseline. Participants also completed a lifetime physical activity pattern questionnaire as part of a mail survey done in 1986. Self-reported physical activity from the 1986 questionnaire will be used to categorize participants' physical activity levels for the years 1971-1985. These recalled levels of activity will be compared to physical activity and physical fitness levels assessed during those same years at the baseline examinations (measure of truth). For example, participants who reported in the 1986 survey that they engaged in relatively high levels of physical activity in 1976 are expected to have recorded higher levels of physical fitness at the 1976 examination than participants who reported in 1986 that they were relatively sedentary in 1976. The study design will permit evaluation of how accurately participants can recall their physical activity up to 15 years in the past and will allow quantification of the errors investigators might expect from such assessments. Validation of long-term recall of activity can lead to the application of lifetime physical activity patterns questionnaires. Data on lifetime activity patterns will be useful in case-comparison and prospective studies of cardiovascular disease.